1. Field of the Invention
This invention relates to a device comprising a self-retractable guide for centering and for vertically restraining pallets of less than full width in a transport vehicle, such as an airplane. In the preferred embodiment, the device presents only rolling surfaces to pallets.
2. Background of the Invention
It is common in transport vehicles, such as airplanes, to have a floor structure and rollers connected to the floor structure and defining a roller plane for rollingly supporting pallets above the floor structure such that the pallets may roll longitudinally. Vertical restraints, connected to the floor structure, hold the pallets down. The term "pallet" is used in this disclosure to include unit load devices including containers. A common pallet has a width of 125 inches, a length of 88 inches, a thickness of up to approximately five-eighths inches, and radiused corners of two inch minimum radius.
It is sometimes desirable to use pallets of different sizes. Commonly, full size and "half" size pallets are used. For example, a full pallet may have a width of 125 inches and a length of 88 inches so that side guides and side vertical restraints spaced 125 inches apart guide the moving pallet and vertically restrain the outer sides. The lateral sides are typically vertically restrained by lock heads that retract below the roller plane. A complementary "half" pallet may have a width of 61.5 or 62 inches and a length of 88 inches such that a small longitudinal space remains between half pallets. This space can be used for half pallet centerline guide and vertical restraint devices.
Some conventional guides and vertical restraints for smaller pallets are manually erected and retracted such that a person must do this when time is critical. Also, conventional guides and vertical restraints do not present a rolling surface to a pallet, rather the pallets scrape against the device. Consequently, with conventional devices, galling and considerable wear of both the pallet and the device occur.
Therefore, there has been a need for an improved guide and vertical restraint device for smaller pallets that is self erecting and retracting and that only presents rolling surfaces to a pallet.